Aramid Nanofiber and Boron Nitride Nanosheet Composite Films for Mechanical and Dielectric Insulation Application

In this work, we obviously enhanced the mechanical and dielectric insulation properties of the aramid nanofiber (ANF) film only by mixing a small amount of two-dimensional boron nitride nanosheets (BNNSs) (0.09 wt %), which were in situ introduced as the assistor of aramid splitting. The composite nanofilm exhibited a tensile stress of 282 MPa and a dielectric breakdown strength of 100.7 kV·mm–1, which increased by 55.8 and 149.3%, respectively. These improvements may be attributed to the introduction of BNNSs, which made the films denser and more horizontally ordered, as well as the enhanced interfacial interactions between individual ANFs. Meanwhile, the ANF/BNNS film also shows high thermal stability, self-extinguishing properties, and excellent chemical stability simultaneously. This work provides a strategy to enhance the mechanical and dielectric insulation properties of ANF-based nanocomposites.